Houses and shops were illuminated with tiny coloured lamps, 'diyas' were lit in the evening hours and light-emitting fireworks came out in sky as dusk fell.
The state government has banned crackers.
Police have seized huge amount of fireworks during drives in last one week to contain the trend.
Long queues were seen before famous temples like Dakshineswar, Kalighat and Adyapith in different parts of the city.
Besides opening special control rooms, both the state and city police also maintained a strict vigil to avert any untoward incident during the celebrations.
Governor M K Narayanan and Chief Minister Mamata Banerjee conveyed their Diwali wishes to the people.
Besides areas like Amherst Street and Chetla in the city, large crowds were also seen before major community Kalipuja pandals at Barasat, Madhyamgram and Naihati in North 24-Parganas district.
Meanwhile, a fire broke out at a paper godown in north Kolkata. No casualty was reported in the incident.